From time to time, I get what I call “dancing crystals” in my vision, in one eye only. It starts off as a shot of a single white “arch”, that looks like a shard of glass, which lasts just a few seconds then goes away, and within seconds it then develops into more and more “crystals” of various colours until all I see in that eye are these crystalline shards dancing about. This lasts from 10-60 minutes, and I can’t really see properly during these attacks as it blurs my vision with these coloured shards of crystal dancing about.

I used to suffer from bad headache-type migraines as a teenager, some lasting months. These days, I get TN, migraines and/or migraine-like or other headaches or pains, and now this.
  ‘A shimmering spectrum of colour’ – the pain and beauty of retinal migraines | Life and style | The Guardian WWW.THEGUARDIAN.COM This rare migraine condition causes brief episodes of disturbances in one eye. Here, sufferers reveal what it is like
I never really quite knew what my “dancing crystals” were, I assumed it was another of those MS neurological things, but now I can guess what it is. As mine are still there when I close my eye, it would appear to be migraine with aura, but I don’t get the headache or any other symptom with it, although the affected eye might ache slightly for a little while. I’ve never had it whilst I’m having a TN attack or other type of headache/pain (which I seem to be having all the time at the moment).

It’s not to be confused with optic neuritis, or phosphenes (which I also get, as a quick white flash), as that causes a different type of visual disturbance, which I once also had, like in the image here:
  optic neuritis - multiple sclerosis encyclopaedia WWW.MULT-SCLEROSIS.ORG
Have any of you experienced these “dancing crystals” and, if so, how would you describe it?